Means for regulating the velocity of rotation of turbines of grinding-mills.



.No. '783,131.- PATENTED FEB. 21, 1905. N. PEDERSEN. MEANS FORREGULATING THE VELOCITY 0P ROTATION OP TURBINES 0F GRINDING MILLS.

APPLIOATION FILED 1330.6- 1902.

2 BHEETB-SHEBT 1,

NO. 783,131 PATENTED FEB. 21, 1905.

N. PBDERSEN. MEANS FOR REGULATING THE VELOCITY 0P ROTATION OF TURBINES OP GRINDING MILLS.

APPLICATION FILED DEO.6, 1902.

, 2 SHEETS-SHEET 2.

IINTTED STATES Patented February 21, 1905.

PATENT riucn,

MEANS FOR REGULATING THE VELOCITY OF ROTATION OF TURBINES OF GRINDING-MILLS.

SPECIFICATION forming part of Letters Patent No. 783,131, dated February 21, 1905.

7 Application filed December 6, 1902. Serial No. 134,176.

To It whom it may concern.-

Be it known that I, NILs PEDERSEN, a subject of the King of Sweden and Norway, residing at Borregaard,near Sarpsborg,Norway, have invented certain new and useful Improvements in Means for Regulating the Speed of Rotation of Driving-Shafts; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form apart of this specification,and in which Figure 1 is an elevation partly in section, and Fig. 2 a vertical section through the cylinders, with the grinding-Wheel in elevation. I

My invention resides in the provision of means for automatically regulating the speed of driving-shafts, and is particularly applicable to the driving-shafts of multiple-cylinder wood-grinding machines, in which relation I will now describe my improvements.

As is well known, the grinding of wood for the manufacture of pulp is now generally effected by machineswherein the wood is fed to a grinding-wheel by the pressure of a fluid as water, for instanceacting on apiston carrying a follower. Ithas been the common practice to arrange a series of wood-grinding machines of the type referred to in tandem, the grinding-wheels thereof being driven by a line-shaft. The singlecylinder machines have practically gone out of use, multiplecylinder machines having taken their place, each provided usually with three piston-cylinders grouped radially about the grindingwheel, and a number of such are commonly driven by one and the same driving-shaft. It is obvious that when the pistons of all the machines are feeding wood to their respective grinding-wheels and the driving-shaft is rotated at the required speed, which may be assumed to be the normal speed, and one or more of the cylinders are cut off from the source of supply of pressure the speed of the shaft will increase in accordance with the reduction of pressure on the grinding-wheels. To avoid this disadvantageous increase of the speed of rotation of the grinding-wheels,hand-operated, means have been provided for controlling the speed of the driving-shaft, either through the motor or otherwise.

The object of this invention lies in the provision 'of means whereby the speed of rotation of the driving-shaft,consequently of th g ing wheel or wheels, is automatical y C011- trolled. This I attain by controlling th P sure of thefluid that acts upon the feed-I through the driving-shaft, so that said W sure will increase above a normal pressure whenever the speed'of rotation of the d rivingshaft increases above a normal speed, the increased pressure on the feed-pistons resulting in a correspondingincreased pressure on the driving-shaft through the wood being ground up, which thus acts as a brake for the shaft- A convenient and simple manner of attaining the object of my invention is to drive the compressing'or force pump from the drivingshaft, and for this purpose I prefer to make use of a centrifugal pump, the pressure produced thereby being proportional to the square of its speed of rotation, as is well known, and gear its shaft to the line-shaft by suitablyproportioned gearing.

That my invention may be fully understood I will describe the same by reference to the accompanyingdrawings, wherein as an example I have shown a single multiple-cylinder grinding machine, its drivingshaft, motorhousing, and means for automatically controlling the speed of said shaft, the view being an elevation partly in section.

In said drawings, A indicates the motorhousing, which is presumed to be a turbine; B, the driving-shaft; C, the grinding-machine; E, the centrifugal pump; F, its shaft, geared by suitable proportional gearing G and H to said driving-shaft, and L the tank which supplies water to the pump E.

The grinding-machine G is of well-known construction and of the type hereinabove referred to and is supposed to have three piston-cylinders N disposed radially about the grinding-wheel W. The rods of the piston D extend through the inner head of their respective cylinders, and each of said rods carries a follower F. The opposite ends of the cylinders are connected through branches/v k of a branch pipe K with the forcing-pipe I of the pump, the connections of one of the cylinders only being shown, and said pipe K is provided with a suitable valve (conventionally indicated at o) to admit water under pressure to either end of the cylinder or to exhaust the water from either end of said cylinder and conduct it to the tank L through exhaust-pipe P.

As hereinabove stated, grinding-machines as above outlined are well known and commonly used, and hence no structural features of these machines are embraced in this invention, and inasmuch as it is also a common practice to arrange a number of machines in tandem and drive their grindingwheels by a shaft common to all of them I. have deemed it unnecessary to illustrate more than one machine in order to enable those skilled in the art to fully comprehend the nature of my invention. 1

It will be readily understood from the description of my invention that if one or two pistons D were relieved of pressure by cutting off the supply of pressure fluid, and thereby arresting the feed-motion of the piston or pistons, the speed of rotation of the drivingshaft B would increase in proportion to the reduction of pressure on the grinding-wheel.

v This of course would proportionally accelerate the operation of the pump and correspondingly increase the pressure on the feed piston or pistons not so relieved from pressure. The result of this will be a correspondinglyincreased pressure of the wood being ground on the grinding-wheel, the wood thus performing the function of a brake relatively to the driving-shaft, reducing its speed of rotation in proportion to the increase of pressure exerted on the grinding-wheel or to a normal speed.

I have referred herein to a turbine as a motor for the driving-shaft. It will be obvious, however, that any other motor may be used.

Having now described my invention, what I claim as new therein, and desire to secure by Letters Patent, is

1. The combination with a revoluble element, a driving element therefor, a piston normally under the pressure of a fluid tending to move the piston toward said revoluble element; of means to supply fluid under pressure to the piston and driven by the driving element to supply fluid to the piston and produce pressure thereon proportional to the speed of the driving element and revoluble element, thereby controlling the speed of the revoluble element and driving element, substantially as set forth.

2.' The combination with a wheel, a driving-shaft therefor, followers and pistons therefor; of a centrifugal pump driven by the driving-shaft, a pipe connection between the pump and pistons to supply fluid under pressure to the pistons, and thereby control the speed of the wheel and shaft, substantially as set forth.

3. The combination with a wheel, cylinders, pistons therein and followers connected to the pistons; of a device to drive the wheel and a centrifugal pump to vary the pressure on the pistons proportional to the speed at which the wheel is driven, substantially as set forth.

In witness whereof I have hereunto set myhand in presence of two witnesses.

NILS PEDERSEN. Witnesses:

ALFRED J. BRYN, J 011. VAALER. 

